I have a bunch of info on parkades... will see if I can dig up some *.pdf files to post for you.
The design of the parkade is first line. You have to use a hard durable concrete and adequate concrete cover to reinforcing. You should also have well defined slopes (1.5% is OK, and proper drainage. You have to pay particular attention to expansion joints, expensive ones or ones that don't work so well and will cause future problems. You should also design in means of maintenance in the form of readily accessible hose bibs for flushing. For over 40 years, I've been providing the client with a scheduled maintenance manual for annual, bi-annual, and five and ten year items to check and look after. I'll try to locate a copy of this to attach, too. You have to decide early on what type of traffic coating you intend to use and on what areas. Parking spots, drive isles and ramps all get varying amounts of wear. Just for a start...
Dik